Object used for particle render getting direction flipped when particle system applied to target with curve modifier
Look at https://blender.stackexchange.com/a/172271/35559 for some updates or possible fix.

Meanwhile, not really sure what's happening but even on a simple non cyclic curve, you can see the beltlink flipping orientation as it moves along the Y axis as soon as it reaches a curve control point (which is aligned and "flat"). May be a bug, something linked with the way curve control points are impacting the Array Modifier...

For some reason, it does not behave that way on all control points.